1998 Lincoln Reverse

I have the coin and it's not a counterbrockage. The extra letters are die-struck. They sit atop a thin crescent that lies above the level of the field but below the level of the design rim. This is a die attrition error in combination with a form of Machine Doubling that is most closely related to rim-restricted design duplication. It's not classic RRDD because the extra letters are not on the rim; instead they occupy the relatively elevated crescent of metal generated by the die attrition error.

I am assuming that this coin was struck with inverted dies (reverse die as hammer die). This pattern of die installation was less common in 1998 than the conventional die setup (obverse die as hammer die) but by the same token it wasn't particularly rare. During a period when the hammer die was misaligned toward the south, the edge of the field portion of the die was worn away by repeated collisions with the beveled entrace of the collar. When the die returned to center, the coins it struck were left with a raised featureless crescent where coin metal flowed into the gap created by the missing portion of the die face. The hammer die was still unstable. When this particular coin was struck, the hammer die bounced up shifted to south, and landed lightly on the featureless crescent, generating a second partial set of letters.

Wow...I have to read Mike's explanation a few times to let it sink in.

I can't believe I understood that whole thing completely, but I do. Thanks Mike! And cool coin Still Lookin.

This specimen raised the possibility of finding extra raised letters on the tops of Cuds, interior die breaks, split dies, and any other abnormal elevation generated by a broken or damaged die. All you need after the initial strike is a high bounce, a lateral shift, and a light touch-down. So keep your eyes open!

The article will appear tomorrow in the online edition of Coin World. They've already placed a version in the public domain, sans photos:

http://www.coinworld.com/insights/d...tters.1.html